When an opening in tissue is created either through an intentional incision or an accidental wound or laceration, biological healing of the opening commences through the proximity of living tissue. If the opening is very large or if its location subjects the wound to continual movement, a physician will seek to forcibly hold the sides of the incision or wound in close proximity so as to promote the healing process. The most prevalent method for forcibly holding tissue closed is through the use of a suture or “stitches.” Sutures also are used to ligate (tie-off) vessels, arteries and fluid carrying ducts by encircling the vessels and occluding flow within the vessel by tightening the suture around the vessel. Sutures may also be placed to suspend or stabilize anatomic structures or to secure or locate implants.
Since at least the second century, practitioners have used sutures in various forms. The early Greeks used sutures comprised of gut. As time passed other natural materials including leather, horsehair, flax, cotton and silk were also used. Over the past century, advances in the material sciences have fostered the creation of polymeric sutures and specially formulated synthetic sutures that are readily absorbed by the body.
Despite the changes and advances in physical composition, the basic suture method has remained unchanged. In order to suture a tissue incision or wound two items are required. The first item is a tissue-piercing device, typically a needle that includes a holding mechanism. The second item is a length of suture that will interface with this holding mechanism. The physician forcibly approximates two sides of the incision or wound being sure that the living tissue is brought into contact. The physician then inserts the tissue piercing device through one side of the tissue and into and through the second side. As the tissue piercing device passes through the tissue, it pulls the suture material through as well so that the suture spans the tissue incision or wound. Using the suture, the physician then ties a knot and cinches the incision or wound closed. Depending on the size of the opening, a physician will repeat the process to effectuate closure across the length of an incision or wound.
Due to advances in modern surgical procedure, sutures are being used in many locations throughout the body including internal sites accessed by endoscopic, laparoscopic, or orthoscopic tools. Depending on the location, access to the surgical site may be limited creating difficulties with proper knot tying. These difficulties can lead to ineffective suture closure as well as increased closure times. Ultimately, these difficulties lead to increased surgical risks to the patient as well as adverse economic effects derived from longer closure times.
Recognizing the inherent difficulties associated with suture knots, a number of different approaches have been pursued by inventors. One approach has been to develop tools or apparatus for tying or assisting in tying the suture. Examples of such inventions include U.S. Pat. No. 5,776,150 to Nolan et al., U.S. Pat. No. 5,984,933 to Yoon, and U.S. Pat. No. 6,152,934 to Harper et al.
An altogether different approach for endoscopic or open surgery applications has been to replace the suture knot completely. Typically, this is accomplished by providing a mechanical gripping device that holds the ends of the suture in place. In some instances, this gripping device has taken the form of a one-piece clip. Examples of one-piece clips include U.S. Pat. No. 5,160,339 to Chen et al., U.S. Pat. No. 5,234,449 to Bruker et al., U.S. Pat. No. 5,330,442 to Green et al., U.S. Pat. No. 5,409,499 to Yi, U.S. Pat. No. 5,645,553 to Kolsea et al., and U.S. Pat. No. 5,665,109 to Yoon. In other cases, the device has taken the form of a two-piece clip. An example of a two-piece clip includes U.S. Pat. No. 5,282,832 to Toso et al. In other instances, the device requires a bore for fenestration or threading of the suture through the bore so the suture can be held by a knot or an interference fit. Examples of devices which use a bore include U.S. Pat. No. 5,514,159 to Matula et al., U.S. Pat. No. 5,630,824 to Hart, U.S. Pat. No. 6,066,160 to Colvin et al., U.S. Pat. No. 6,126,677 to Ganaja et al., U.S. Pat. No. 6,200,329 to Fung et al., and U.S. Pat. No. 6,293,961 to Schwartz et al. Finally, other approaches have used gripping devices created through welding of suture material or other holding elements. Examples include U.S. Pat. No. 6,358,271 to Egan et al., and U.S. Pat. No. 6,106,545 to Egan.
While these mechanical gripping devices have improved the speed and reliability of internal sutures, there remain considerable drawbacks. Many of the aforementioned gripping devices require fenestration of the suture through a bore prior to the closure of the device. Depending on the suture location, threading through this fenestration may be nearly as difficult and time consuming as tying a knot. Many of the devices have closure mechanisms that make it nearly impossible to design applicators capable of reloading and applying additional fasteners without withdrawing the applicator from the suture site. In addition, many of the applicators have little or no adjustment capacity once the closure device is applied should a physician need to further cinch and/or adjust the suture tension. What is needed in the art is a suture clip design that overcomes these limitations.